/**
 * @fileoverview HTML reporter
 * @author Julian Laval
 *
 * Updated for use with sass-lint under MIT licence
 * @license https://github.com/sasstools/sass-lint/blob/master/lib/format/LICENSE
 */

'use strict';

const lodashTemplate = require('lodash.template');
const lodashMap = require('lodash.map');
const fs = require('fs');
const path = require('path');

//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------

const pageTemplate = lodashTemplate(fs.readFileSync(path.join(__dirname, 'html-template-page.html'), 'utf-8'));
const messageTemplate = lodashTemplate(fs.readFileSync(path.join(__dirname, 'html-template-message.html'), 'utf-8'));
const resultTemplate = lodashTemplate(fs.readFileSync(path.join(__dirname, 'html-template-result.html'), 'utf-8'));

/**
 * Given a word and a count, append an s if count is not one.
 * @param {string} word A word in its singular form.
 * @param {int} count A number controlling whether word should be pluralized.
 * @returns {string} The original word with an s on the end if count is not one.
 */
const pluralize = function (word, count) {
  return (count === 1 ? word : `${word}s`);
};

/**
 * Renders text along the template of x problems (x errors, x warnings)
 * @param {string} totalErrors Total errors
 * @param {string} totalWarnings Total warnings
 * @returns {string} The formatted string, pluralized where necessary
 */
const renderSummary = function (totalErrors, totalWarnings) {
  const totalProblems = totalErrors + totalWarnings;
  let renderedText = `${totalProblems} ${pluralize('problem', totalProblems)}`;

  if (totalProblems !== 0) {
    renderedText += ` (${totalErrors} ${pluralize('error', totalErrors)}, ${totalWarnings} ${pluralize('warning', totalWarnings)})`;
  }
  return renderedText;
};

/**
 * Get the color based on whether there are errors/warnings...
 * @param {string} totalErrors Total errors
 * @param {string} totalWarnings Total warnings
 * @returns {int} The color code (0 = green, 1 = yellow, 2 = red)
 */
const renderColor = function (totalErrors, totalWarnings) {
  if (totalErrors !== 0) {
    return 2;
  }
  else if (totalWarnings !== 0) {
    return 1;
  }
  return 0;
};

/**
 * Get HTML (table rows) describing the messages.
 * @param {Array} messages Messages.
 * @param {int} parentIndex Index of the parent HTML row.
 * @returns {string} HTML (table rows) describing the messages.
 */
const renderMessages = function (messages, parentIndex) {

  /**
   * Get HTML (table row) describing a message.
   * @param {Object} message Message.
   * @returns {string} HTML (table row) describing a message.
   */
  return lodashMap(messages, message => {
    const lineNumber = message.line || 0;
    const columnNumber = message.column || 0;

    return messageTemplate({
      parentIndex,
      lineNumber,
      columnNumber,
      severityNumber: message.severity,
      severityName: message.severity === 1 ? 'Warning' : 'Error',
      message: message.message,
      ruleId: message.ruleId
    });
  }).join('\n');
};

/**
 * @param {Array} results Test results.
 * @returns {string} HTML string describing the results.
 */
const renderResults = function (results) {
  return lodashMap(results, (result, index) => resultTemplate({
    index,
    color: renderColor(result.errorCount, result.warningCount),
    filePath: result.filePath,
    summary: renderSummary(result.errorCount, result.warningCount)

  }) + renderMessages(result.messages, index)).join('\n');
};

//------------------------------------------------------------------------------
// Public Interface
//------------------------------------------------------------------------------

module.exports = function (results) {
  let totalErrors,
      totalWarnings;

  totalErrors = 0;
  totalWarnings = 0;

  // Iterate over results to get totals
  results.forEach(result => {
    totalErrors += result.errorCount;
    totalWarnings += result.warningCount;
  });

  return pageTemplate({
    date: new Date(),
    reportColor: renderColor(totalErrors, totalWarnings),
    reportSummary: renderSummary(totalErrors, totalWarnings),
    results: renderResults(results)
  });
};
